Energy storage is increasingly becoming a possible solution worldwide to aid the energy supply and demand. The objective of this study is to determine whether thermal energy storage can be effectively and efficiently achieved by ways of electromagnetic (EM) radiation. To serve this purpose, an experimental setup was designed in order to subject core flooding experiments to EM heating using a MW source. Temperature data is obtained and used to construct temperature profiles as well as energy absorption and storage profiles. The experiments vary from EM radiation under no flow conditions to experiments inducing flow in order to determine the effect of flow on energy absorption and storage amounts. The results obtained show that a significant amount of energy is absorbed by the core and that the introduction of flow at the chosen flowrates during EM heating does not diminish the energy absorption ability of water inside the core. Flow does however increase the rate of energy decline within the core when EM heating is stopped thus reducing the amount of energy stored. Nevertheless, around 40% of the energy absorbed after 150 seconds of EM heating is stored in the core after a cooling period of 60 minutes. This amount declines significantly when flow in implemented throughout heating and cooling. Even though the experimental setup performed accordingly, the large amounts of energy losses are an area that should be subject to improvement. When this technology is implemented in reservoirs or aquifers, the MW antenna is placed in the pay zone. This results in lower energy losses due to the over- and underlying formations functioning as insulation. Subject to improvements, this study concludes that EM stimulated core flooding is a legitimate and viable technology with significant potential for thermal energy storage purposes."

The rapid degradation of the Thorn-sandstone could be explained by the presence of organics or minerals such as swelling glauconite, oxidized glauconite or non-swelling clays sensitive to hydric variations despite being non-swelling. A variety of tests and observations have been carried out to identify the most likely process of degradation. Conventional optical microscopic observations, XRF and XRD analyses, Methylene Blue tests on rock powder, Methylene Blue staining of thin-sections, and Loss-on-Ignition have been conducted as well as more advanced observations using X-ray micro-computed tomography (micro-CT) and Scanning Electronic Microscopy (SEM). The micro-CT scans allowed the visualization of the grain arrangement in 3D along with the network of micro-fissures spread around within the material. The SEM combined with EDEX measurements allowed the visualization of grains in 2D in great detail along with determining chemical elements at the sub-grain scale. Combined results showed that the Thorn-sandstone consists of quartz grains along with some grains of hematite, rutile or ilmenite. Porosity (excluding fissures) is very low. The grains are tightly packed and surrounded by a very heterogeneous fine-grained brown material. This brown material consists of a mixture of minerals, possibly clays, chlorite , micas, weathered glauconite and feldspar as well as small grains of rutile, hematite or ilmenite. The aforementioned Micro-fissures run through the brown material. The sensitivity of the brown clayey material to water, when exposed to wetting and drying cycles, is likely to explain the degradation of the Thorn-sandstone. Other hypotheses could be formulated to explain the rapid deterioration of the Thorn sandstone.